In 1958 at 15 he was the world’s youngest grandmaster.
If we look at his early recorded games we encounter evidence of a remarkably mature approach to playing chess.
How did this self-taught Brooklyn boy become so good so fast? In particular, whence the early maturity of style?
The clue may be found in his unusual beginnings. Chessboards have two sides to accommodate two players. But Bobby’s early experiences were solitary.
When his sister Joan defaulted as an opponent, later explaining that “we Fischers do not like to lose,” the younger brother - abandoned to his own resources - had to do it alone.
He would first make a move from one side of the board, then from the other.
We can imagine Bobby Fischer with the black pieces playing Bobby Fischer with the white pieces. Both of his avatars, Bobby One and Bobby Two, of course, unwilling to give an inch or cede a single square. As much as each passionately wanted to win, each hated even more to lose.
Willy-nilly, the games would have mimicked the wariness of modern grandmaster play.
Did this kind of play boost his early maturity.
Is this fanciful reconstruction realistic? There is no way to know.
But we do know that he had an enormous capacity to do it alone. Perhaps an interval of solitaire chess, Fischer-style, did play a role in his early development?

Below is a win by Hao Wang against Anish Giri from the FIDE Grand Prix in Beijing, China.

FIDE Grand Prix

Hao Wang Anish Giri

1. d4 ..... d6
2. e4 ...... Nf6
3. Nc3 ..... e5
4. Nf3 ..... N(b)d7
5. Bc4 ..... exd4
6. Qxd4 .... Be7
7. Bxf7ch .. Kxf7
8. Ng5ch ... Ke8
9. Ne6 ..... c5
10. Qd1 ..... Qb6
11. Nxg7ch .. Kf7
12. Nf5 ..... Bf8
13. O-O ..... d5
14. Nxd5 .... Nxd5
15. Qxd5ch .. Ke8
16. Bg5 ..... Qg6
17. R(a)d1 .. Rg8
18. f4 ...... a5
19. e5 ...... Qxf5
20. Qxg8 .... Ra6
21. R(f)e1 .. Rg6
22. e6 ...... Black resigns